I just got done fixing this on my boat. I wasn't experiencing water leaking. Just noticed that the fit was a little lose when I pulled my raw water hose off for winterizing. I used some black silicone rtv. Did the same with my exhaust flanges coming thru the hull, back this spring. Where I noticed the oem silicone had dried out and allowed some leaking.

Cleaned up the bulk head fitting.

Put a nice bead of rtv on the inside and out then re-sandwiched the bulk head thru the hull.